JP4008685B2 - Hydraulic control device for automatic transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic control device for an automatic transmission.
[0002]
[Prior art]
The automatic transmission includes a rotating element including a planetary gear set in the speed change mechanism, and also includes an engaging element such as a clutch or a brake for engaging and releasing between the rotating elements. Each of the fastening elements is operated by hydraulic pressure, and a plurality of shift stages are obtained by fastening and releasing the fastening elements in a predetermined combination.
FIG. 11 shows an example of supplying hydraulic pressure to the clutch which is a fastening element. That is, the line pressure using an oil pump (not shown) as a generation source is regulated by the pressure regulating valve 10 controlled by the solenoid 11 and supplied to the clutch 40.
[0003]
The pressure regulating valve 10 receives the control pressure from the solenoid 11 at one control end, feeds back the output pressure to the other control end, and maintains the output pressure corresponding to the control pressure.
A hydraulic switch 13 is provided in the oil passage 42 between the pressure regulating valve 10 and the clutch 40, and detects the operation timing of the clutch 40 from the clutch pressure in the course of the hydraulic charging of the clutch 40 or the drain. With this operation timing, hydraulic control between the related fastening elements is performed so as to realize a quick and smooth shift.
[0004]
In addition, if there is an abnormality in the hydraulic control device and the hydraulic pressure is supplied contrary to the intention of draining the hydraulic pressure, or if the hydraulic pressure is drained contrary to the intention of supplying the hydraulic pressure, the clutch or The brake is engaged and released, and it becomes a dangerous state due to an interlock or neutral state. However, by detecting the supply of hydraulic pressure and the drain state with the hydraulic switch 13, such a state can be detected quickly and accurately, Control is performed to avoid dangerous situations.
[0005]
[Problems to be solved by the invention]
Here, in the shift to the gear position where the clutch 40 is engaged, the pressure regulating valve 10 increases the command pressure higher than the line pressure from the solenoid 11 in order to maintain the engaged state at the time of non-shift after the completion of the shift. Upon receiving the instructed control pressure, the output pressure from the pressure regulating valve 10 to the clutch 40 becomes the same as the line pressure.
That is, at this time, the line pressure is not reduced and supplied to the clutch 40 as it is.
As shown in FIG. 12, the pressure regulating valve 10 is provided with a spool 35 in a valve hole 31 having an input port 32, an output port 33, and a drain port 34 so as to allow a stroke. Line pressure is supplied to the input port 32, and the output port 33 is connected to the clutch 40.
[0006]
During so-called pressure adjustment where the command pressure is lower than the line pressure, the control pressure (SOL pressure) from the solenoid 11 is small, and the land 36 of the spool 35 closes the input port 32 as shown in FIG. A diaphragm S1 is formed by the gap between the valve holes 31, the land 37 of the spool 35 closes the drain port 34, and a diaphragm S2 is formed by the gap between the land 37 and the valve hole 31. Oil leaking from the throttle S1 increases the hydraulic pressure of the output port 33, and oil leaking from the throttle S2 reduces the hydraulic pressure of the output port 33.
[0007]
When the hydraulic pressure of the output port 33 formed by the balance is larger than the hydraulic pressure corresponding to the SOL pressure, the feed pressure acting upward from the lower side of the spool 35 in the figure increases, and the spool 35 is shown in the drawing. By stroking upward, the stop S1 is further stopped, and the stop of the stop S2 is loosened.
As a result, the oil leaking from the throttle S1 is reduced and the oil leaking from the throttle S2 is increased, and as a result, the hydraulic pressure of the output port 33 is lowered.
[0008]
When the hydraulic pressure of the output port 33 formed by the balance is smaller than the hydraulic pressure corresponding to the SOL pressure, the feed pressure acting upward from the lower side of the spool 35 in the figure is reduced, and the spool 35 is shown in the drawing. By making the stroke downward, the stop of the stop S1 becomes loose, and the stop of the stop S2 is further reduced. As a result, the oil that leaks from the throttle S1 increases and the oil that leaks from the throttle S2 decreases, and as a result, the hydraulic pressure of the output port 33 increases.
[0009]
While repeating the above action, the hydraulic pressure of the output port 33 converges to the hydraulic pressure corresponding to the SOL pressure, and forms the hydraulic pressure corresponding to the SOL pressure.
As a result, when such a pressure regulation state is maintained, the hydraulic pressure from the input port 32 is reduced by the throttle S1, and from the drain port 34 when a higher hydraulic pressure than the balanced hydraulic pressure is formed. Since the oil is discharged, even if the oil pressure fluctuates extremely greatly at the input port 32, the fluctuation is attenuated and transmitted to the output port 33.
[0010]
On the other hand, when the command pressure value is higher than the line pressure and therefore the control pressure from the solenoid 11 is also large, the input port 32 is not throttled by the land 36 as shown in FIG. Since the drain port 34 is also almost closed, the hydraulic pressure hardly leaks from here.
For this reason, if there is oil vibration generated in the line pressure due to the structure of the oil pump, the oil vibration is applied to the hydraulic switch 13 as it is.
[0011]
When the oil vibration is high frequency, the average value of the hydraulic pressure including the oil vibration actually determines the torque transmission capacity of the clutch. Therefore, if this average value is called the effective pressure, it acts on the clutch 40. Even if the effective hydraulic pressure is low, if the instantaneous hydraulic pressure exceeds the allowable pressure allowed as the hydraulic pressure input of the hydraulic switch due to the oil vibration, the hydraulic switch and the surrounding hydraulic circuit will respond for the reason of its application. Therefore, the hydraulic pressure exceeding the permissible pressure acts on the hydraulic switch as it is, causing a failure of the hydraulic switch.
[0012]
Further, when the oil vibration acts at a high frequency and the oil pressure on the side where the amplitude of the oil vibration is smallest falls below the oil pressure at which the oil pressure switch is turned off, the oil pressure switch is repeatedly turned on and off accordingly. However, there is a limit to the number of times that the hydraulic switch can correctly detect on and off, and the hydraulic switch cannot correctly detect on and off when the allowable number of times of durability is exceeded. The high-frequency oil vibration causes the hydraulic switch to be turned on and off at a high frequency, and a large number of hydraulic switches are repeatedly turned on and off in a short time, so that the durability of the hydraulic switch 13 is significantly impaired. Will be.
[0013]
Therefore, in view of the above-described problems, the present invention provides a hydraulic control device for an automatic transmission that improves the durability of a hydraulic switch that detects the hydraulic pressure of a fastening element so that the hydraulic switch is not affected by the oil vibration of the line pressure. The purpose is to provide.
[0014]
[Means for Solving the Problems]
  For this reason, the present invention of claim 1 includes a plurality of fastening elements that are hydraulically operated with a plurality of rotating elements, and is configured to obtain a plurality of shift stages by a combination of fastening and releasing of the fastening elements. In an automatic transmission in which a hydraulic switch is provided in a hydraulic pressure supply path of a predetermined fastening element to which pressure is supplied via a pressure regulating valve,A line pressure control means for controlling the line pressure;A fastening state determination means for determining whether the control state of each fastening element is in a fastening state;For a fastening element provided with a hydraulic switch that has been determined to be in a fastening state, the line pressure is controlled to a predetermined value or more that corresponds to the magnitude of the oil vibration that affects the durability of the hydraulic switch. While the line pressure was controlled by the means, it was determined that the fastening state was presentIn order to maintain the output of the pressure regulating valve of the fastening element lower than the line pressure, the pressure regulating valveWhile the line pressure is less than the predetermined value, the output of the pressure regulating valve of the fastening elementAnd a protection control means.
  Even when the fastening element is in the fastening state, since the pressure regulating valve is in the pressure regulating state, the transmission of the oil vibration contained in the line pressure is attenuated, and a large pressure exceeding the effective pressure is prevented from being applied to the hydraulic switch at a high frequency. The
[0015]
  The invention of claim 2Instead of line pressure, while the engine speed is above the specified value,Control was performed so that the output of the pressure regulating valve was kept lower than the line pressure.This also attenuates the transmission of the oil vibration contained in the line pressure, and prevents a large pressure exceeding the effective pressure from being applied to the hydraulic switch at a high frequency.
[0016]
  Claim 3According to the invention, the pressure regulating valve includes a spool and forms a throttle with respect to the line pressure in the pressure regulating state.
  Since the throttle is easily formed by the stroke of the spool, the damping of the oil vibration is particularly easy.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 shows an example of a transmission mechanism of an automatic transmission to which a hydraulic control device according to an embodiment is applied.
The speed change mechanism 1 includes a first planetary gear set Gl and a second planetary gear set G2 along the transmission input shaft IN.
The rotational output from the engine output shaft ENG is input to the transmission input shaft IN via the torque converter T / C. A transmission output shaft OUT is provided on the extension of the input shaft IN. A lockup clutch L / U is attached to the torque converter T / C.
The first planetary gear set G1 is a simple planetary gear set including a first pinion Pl, a first carrier Cl, a first sun gear S1, and a first ring gear R1, and the second planetary gear set G2 is a second pinion P2 and a second pinion P2. This is a simple planetary gear set including a carrier C2, a second sun gear S2, and a second ring gear R2.
[0018]
The first sun gear S1 of the first planetary gear set G1 is connected to the transmission input extraction IN via the reverse clutch R / C and can be fixed to the transmission case K by the 2-4 brake 2-4B. . The first carrier C1 that supports the first pinion Pl is connected to the transmission input extraction IN via the high clutch H / C. Further, the first carrier C1 can be fixed to the transmission case K by a low and reverse brake L & R / B and a one-way clutch OWC provided in parallel with each other.
The first ring gear Rl is connected to the second carrier C2 of the second planetary gear set G2.
[0019]
The second sun gear S2 of the second planetary gear set G2 is directly connected to the transmission input extraction IN, and the second carrier C2 is directly connected to the transmission output shaft OUT. The second ring gear R2 is coupled to the first carrier C1 of the first planetary gear set G1 via the low clutch L / C.
By engaging and releasing the clutch or brake engaging elements in a predetermined combination, four forward speeds and one reverse speed are obtained as shown in FIG.
[0020]
FIG. 3 shows a hydraulic control system for operating each of the fastening elements.
The manual valve 2 is a valve that can be switched by a select operation. In the D range, the line pressure is output to the D range pressure oil passage 3, and in the R range, the line pressure is output to the R range pressure oil passage 4.
The pilot valve 5 controls to reduce the line pressure to a constant pilot pressure and outputs it to the pilot pressure oil passage 6.
[0021]
The low clutch pressure oil passage 9 to the low clutch L / C is provided with a pressure regulating valve 7, and the pressure regulating valve 7 is controlled by a solenoid 8 that operates according to a command from the AT control unit 24.
Further, in each oil passage 12 (12a, 12b, 12c) to the high clutch H / C, 2-4 brake 2-4B, and low and reverse brake L & R / B, a pressure regulating valve 10 (10a, 10b, 10c) is provided. Each pressure regulating valve 10 is controlled by a solenoid 11 (11a, 11b, 11c) that operates according to a command from the AT control unit 24. Further, these oil passages 12a, 12b, 12c are provided with hydraulic switches 13 (actuated according to the hydraulic pressure supplied to the corresponding clutches or brakes, that is, the high clutch pressure, the 2-4 brake pressure, and the low and reverse brake pressure. 13a, 13b, 13c).
[0022]
The pressure control solenoid 22 is a duty type, and the line pressure can be controlled to an arbitrary hydraulic pressure between the minimum pressure and the maximum pressure by the control from the AT control unit 24. The lockup solenoid 23 is a duty type and controls the engagement and release of the lockup clutch L / U.
[0023]
A first fail-safe valve 25 and a second fail-safe valve 26 are provided on the input side of the pressure regulating valve 10b of the 2-4 brake 2-4B.
The first failsafe valve 25 uses the low clutch pressure PL / C after being switched by the second failsafe valve 26 as an operation signal pressure.
The second failsafe valve 26 uses the high clutch pressure PH / C as an operation signal pressure.
[0024]
At the third speed in which the low clutch pressure and the high clutch pressure are generated simultaneously, the high clutch pressure is applied to the second failsafe valve 26, whereby the low clutch pressure is applied to the first failsafe valve 25, thereby 2-4. Force the brake pressure to drain.
[0025]
A third fail-safe valve 27 and a measure 4 fail-safe valve 28 are provided on the input side of the pressure regulating valve 10c of the low and reverse brake L & R / B.
The third fail-safe valve 27 uses the high clutch pressure PH / C as the operation signal pressure, and the measure 4 fail-safe valve 28 uses the 2-4 brake pressure P2-4 / B as the operation signal pressure. -4 The brake pressure is drained at the second, third, and fourth speeds when either one or both of the hydraulic pressures of the brake pressure P2-4 / B are generated.
[0026]
The AT control unit 24 receives switch signals indicating the hydraulic states of the respective fastening elements from the respective hydraulic switches 13 (13a, 13b, 13c), and at the time of shifting, each solenoid 8 is switched at a predetermined timing based on the switch signals. , 11a, 11b, and 11c.
In the following, the fastening element is represented by “clutch”.
[0027]
FIG. 4 and FIG. 5 are flowcharts showing the control flow of the gear position and gear shift determination determination in the AT control unit 24.
First, in step 100, a gear stage Gnext intended by the driver is determined based on, for example, a shift line set for the vehicle speed and the throttle opening of the engine.
In step 101, it is checked whether the change of the target shift stage is currently permitted and a new shift is permitted.
[0028]
If the change of the target shift speed is permitted, in step 102, the value of Gnext is entered in the target shift speed Gsft as a variable.
If the change of the target gear position is not permitted in the check in step 101, the current value of Gsft is held in step 103.
[0029]
In step 104 after steps 102 and 103, it is checked whether or not the current gear stage Gcur is different from the target gear stage Gsft.
If the values of Gcur and Gsft are different, it is determined that the current gear shift is in progress and the routine proceeds to step 105 where the control state of each clutch is determined according to the clutch control definition of FIG. 6 and the command pressure to each pressure regulating valve 10 is set. To do.
Here, FIG. 6 is a control definition table showing the control states of the respective clutches with respect to the target shift speed Gsft for each current shift speed Gcur. This control definition table shows only those related to the forward gear.
In step 106, it is checked whether or not a predetermined time has elapsed since the inertia phase in the shift from the current shift stage Gcur to the target shift stage Gsft is completed.
[0030]
If the predetermined time has elapsed from the end of the inertia phase, it is determined that the shift has ended, and in step 107, the value of the target shift stage Gsft is entered in the current shift stage Gcur, and one flow is completed.
If the predetermined time has not elapsed since the end of the inertia phase, this flow is ended and the next flow is started.
[0031]
When the current speed Gcur matches the target speed Gsft in the previous step 104 check, it is determined that the gear is in the non-shift state, and in step 108, the control state of each clutch is determined according to the clutch control definition of FIG. Then, the command pressure to each pressure regulating valve 10 is set.
[0032]
FIG. 7 is a flowchart showing the details of setting command pressures to each pressure regulating valve 10 (more precisely, command pressures to solenoid 11 for pressure regulating valve control) in steps 105 and 108 described above.
First, in step 200, it is checked whether or not the clutch control state is “release → engagement transition control” from release to engagement.
If “release → engagement transition control” is in progress, the process proceeds to step 201, and the command to the solenoid 11 is set to “release of shift control → engagement transition command oil pressure”. Here, based on the engine torque, the vehicle speed, the throttle opening, and the turbine speed, the clutch pressure during the shift period is set to be a predetermined hydraulic pressure.
[0033]
If it is determined in step 200 that the clutch control state is not “release → engagement transition control”, it is determined in step 202 whether the clutch control state is “engagement → release transition control” from engagement to release. To check.
If “engagement → disengagement transition control” is in progress, the process proceeds to step 203, and the command to the solenoid 11 is set to “shift control engagement → disengagement transition command oil pressure”. Here, as in step 201, the clutch pressure during the shift period is set to a predetermined hydraulic pressure.
If it is determined in step 202 that the clutch control state is not “engagement → disengagement transition control”, the process proceeds to step 204 to check whether the clutch control state is “release control”. If it is “release control”, in step 205, the command to the solenoid 11 is set to the minimum command oil pressure.
[0034]
On the other hand, when the control state of the clutch is not “disengagement control”, the control state is “engagement control” and the command to the solenoid 11 is set to the protection hydraulic pressure in step 206.
Here, the protective oil pressure is lower than the line pressure, and is set to 0.8 to 0.9 times the line pressure by the operation of the pressure regulating valve 10, for example.
During shifting, the process proceeds from step 201 and 203 to step 106 of the main flow.
[0035]
FIG. 8 is a time chart of related parameters illustrating the above-described flow for shifting from the second speed to the third speed.
When Gnext changes to the third speed at time t0 while in the second speed gear stage (step 100), the target gear stage Gsft is set to the third speed of Gnext (step 102). As a result, Gcur remains at the second speed, and only Gsft is at the third speed. Therefore, in step 104, Gcur ≠ Gsft is determined, and in step 105, the command pressure is determined.
Further, the 2 → 3 shift is started, and the control state of each clutch is determined by the table of FIG.
[0036]
As a result, the low clutch L / C is engaged, the 2-4 brake 2-4 / B is engaged → release transition control, the high clutch H / C is released → engaged transition control, and the low and reverse brake L & R / B is release control. It becomes.
Therefore, in this case, the first clutch performing the engagement → disengagement transition control shown in FIG. 8 is 2-4 brake 2-4 / B, and the second clutch performing the release → engagement transition control. Is a high clutch H / C in this case. At this time, the hydraulic pressure of the first clutch (2-4 brake 2-4 / B) in the engaged state is temporarily reduced to a predetermined value, and the second clutch (high clutch H / C) in the released state is at the minimum hydraulic pressure. Is supplied with the hydraulic pressure regulated by the pressure regulating valve 10a.
[0037]
When the second clutch is filled with hydraulic pressure at time t1, the hydraulic switch 13a provided in the oil path of the second clutch detects and operates, and based on the switch signal, the AT control unit 24 performs the first control. Start the clutch hydraulic drain.
As a result, the actual gear ratio changes, and when the third phase gear ratio is reached at time t2 and the inertia phase is terminated, the shift control is terminated at time t3 when a predetermined time has elapsed.
[0038]
The clutch pressure of the second clutch that is engaged by the shift is rapidly increased so that the engaged state after the shift can be maintained after the inertia phase is completed.
When the shift is completed, the value of the target shift speed Gsft at the third speed is stored in the current shift speed Gcur. Therefore, Gcur = Gsft = third speed, and at the next control timing, the routine proceeds from step 104 to step 108, where the command pressure in the non-shift state is set.
[0039]
For the first clutch (2-4 brake 2-4 / B), the “engagement → disengagement transition control” for shifting is performed from time t0 to time t3, and for the second clutch (high clutch H / C) Between t0 and time t3 is “release → engagement transition control”.
As also shown in this time chart, the clutch hydraulic pressure is the maximum pressure (based on the maximum command hydraulic pressure) in the period of “engagement control” before “engagement → disengagement transition control” and “release → engagement transition control”. = Protective oil pressure set lower than the line pressure).
[0040]
Although not shown in FIG. 8, as is apparent from the table of FIG. 6, the second speed state before the 2 → 3 shift control, during the 2 → 3 shift control, and after the 2 → 3 shift control is completed. The low clutch L / C that is in the “engagement control” state throughout the third speed state and all the states is also in the protective hydraulic pressure state.
The same applies to the shifts between the other shift speeds and the fastening elements.
[0041]
The present embodiment is configured as described above, and the command pressure is set so that the clutch pressure in the “engagement control” that maintains the clutch engagement state is the protective oil pressure that is lower than the line pressure. As shown in FIG. 12A, a certain pressure regulating valve 10 has a throttle formed by a spool land between an input port and an output port. As a result, the protective oil pressure is only adjusted to a value slightly lower than the line pressure, but due to the presence of the throttle, as shown in FIG. Transmission of the oil vibration to the output port side is greatly attenuated, and the maximum value of the hydraulic pressure amplitude decreases in the oil passage 12 between the pressure regulating valve 10 and the clutch, as shown in FIG. In addition, the allowable pressure of the normal hydraulic switch is set with a margin to the line pressure, so if the hydraulic pressure amplitude is reduced, the maximum value of the hydraulic pressure amplitude will be reduced relative to the allowable pressure of the hydraulic switch. Is possible. As a result, the durability of the hydraulic switch 13 is improved.
Since the protective oil pressure is only slightly lower than the line pressure as described above, there is no possibility of affecting the clutch fastening retention.
[0042]
In the above embodiment, the clutch pressure for the engagement control is always set to the protective hydraulic pressure. However, as a modified example, the clutch pressure is set to the protective hydraulic pressure only when the oil pressure of the line pressure is assumed to be large. Also good.
FIG. 10 is a flowchart showing command pressure setting for each pressure regulating valve 10 in the modification. Here, step 300 is provided between step 204 and step 206 in the flowchart of FIG.
[0043]
If it is determined in step 204 that the clutch control state is not “disengagement control”, it is assumed that the control state is “engagement control”, and the process proceeds to step 300 where the engine speed is equal to or greater than a predetermined value and the pressure control solenoid 22 It is checked whether the pressure is controlled to be a value equal to or higher than a predetermined value.
[0044]
When the engine rotation is equal to or higher than the predetermined value and the line pressure is on the high pressure side, it is assumed that the oil vibration is large, and therefore, in step 206, the command to the solenoid 11 is set to the protective hydraulic pressure. On the other hand, when the engine speed is not equal to or higher than the predetermined value or the line pressure is not on the high pressure side, the routine proceeds to step 301, where the command to the solenoid 11 is set as the maximum command pressure and the line pressure is supplied to the clutch as it is.
As a result, side effects such as deterioration of the durability of the solenoid, noise of the solenoid, and increase in the consumption current of the solenoid, which are concerned by continuing to regulate the pressure regulating valve to the intermediate pressure while improving the durability of the hydraulic switch 13. It is possible to obtain the maximum effect while further reducing the possibility of occurrence.
[0045]
In the present embodiment, the example in which the SOL command pressure is set to the protective hydraulic pressure in the non-shifting state has been described. However, the present invention is not limited to this, and the friction element that continues to be engaged even in the shifting state (2 → 3 in the present embodiment). Needless to say, a low-clutch during a shift) includes a SOL command pressure that is a protective oil pressure even during a shift.
[0046]
【The invention's effect】
As described above, in the automatic transmission in which a hydraulic switch is provided in a hydraulic supply path of a predetermined fastening element to which line pressure is supplied via a pressure regulating valve, the pressure regulating valve of the fastening element provided with the hydraulic switch is provided. Is controlled so that the output of each fastening element is kept lower than the line pressure when each fastening element is performing fastening control, so that the transmission of the oil vibration contained in the line pressure is attenuated, and the oil pressure switch Therefore, it is possible to prevent the application of a large pressure exceeding the effective pressure due to.
[0047]
  In particular,Since the pressure regulating valve is in a regulated state only while the line pressure is equal to or higher than the predetermined value or the engine rotation is equal to or higher than the predetermined valueDetailed control is possible according to the magnitude of the assumed oil vibration.
[0048]
In addition, the pressure regulating valve is provided with a spool and forms a throttle against the line pressure in the pressure regulating state, so that the throttle is easily formed by the stroke of the spool. Is done.
[Brief description of the drawings]
FIG. 1 is a diagram showing a speed change mechanism of an automatic transmission according to an embodiment of the present invention.
FIG. 2 is a diagram showing a combination of fastening and releasing of fastening elements.
FIG. 3 is a diagram showing a hydraulic control system in the embodiment.
FIG. 4 is a flowchart showing a flow of control for determining a shift speed and shift determination.
FIG. 5 is a flowchart showing the flow of control for determining a gear position and shift determination.
FIG. 6 is a clutch control definition table based on a current gear position and a target gear position.
FIG. 7 is a flowchart showing details of command pressure setting of the pressure regulating valve.
FIG. 8 is a time chart showing changes in related parameters during gear shifting.
FIG. 9 is an explanatory diagram showing an effect of damping oil vibration.
FIG. 10 is a flowchart showing command pressure setting of a pressure regulating valve in a modified example.
FIG. 11 is a diagram showing an example of supplying hydraulic pressure to a conventional clutch.
FIG. 12 is a view showing a basic structure of a pressure regulating valve.
[Explanation of symbols]
1 Transmission mechanism
2 Manual valve
5 Pilot valve
7 Pressure regulating valve
8 Solenoid
10, 10a, 10b, 10c Pressure regulating valve
11, 11a, 11b, 11c Solenoid
12, 12a, 12b, 12c Oil passage
13, 13a, 13b, 13c Hydraulic switch
22 Pressure control solenoid
23 Lock-up solenoid
24 AT control unit
25 First fail-safe valve
26 Second fail-safe valve
27 Third fail-safe valve
28 Measure 4 Fail-safe valve
31 Valve hole
32 input ports
33 Output port
34 Drain port
35 spool
36 rand
ENG engine output shaft
G1 first planetary gear set
G2 2nd planetary gear set
2-4B 2-4 brake
H / C High clutch
IN Transmission input shaft
K transmission case
L & R / B Low and reverse brake
L / C Low clutch
OUT Transmission output shaft
OWC one-way clutch
R / C reverse clutch

Claims (3)

A plurality of fastening elements that are hydraulically operated with a plurality of rotating elements, and are configured to obtain a plurality of shift speeds by a combination of fastening and releasing of the fastening elements, and the line pressure is supplied via a pressure regulating valve. In an automatic transmission in which a hydraulic switch is provided in the hydraulic supply path of the fastening element of
A line pressure control means for controlling the line pressure;
A fastening state determination means for determining whether the control state of each fastening element is in a fastening state;
For a fastening element provided with the hydraulic switch, which is determined to be in a fastening state, a line exceeding a predetermined value set in advance corresponding to the magnitude of oil vibration that affects the durability of the hydraulic switch While the line pressure is controlled by the pressure control means, the pressure regulating valve is brought into the pressure regulating state so that the output of the pressure regulating valve of the fastening element determined to be in the engaged state is kept lower than the line pressure, and the line A hydraulic control device for an automatic transmission , further comprising protection control means for keeping the output of the pressure regulating valve of the fastening element as it is while the pressure is less than the predetermined value . A plurality of fastening elements that are hydraulically operated with a plurality of rotating elements, and are configured to obtain a plurality of shift speeds by a combination of fastening and releasing of the fastening elements, and the line pressure is supplied via a pressure regulating valve. In an automatic transmission in which a hydraulic switch is provided in the hydraulic supply path of the fastening element of
A fastening state determination means for determining whether the control state of each fastening element is in a fastening state;
For a fastening element provided with the hydraulic switch, which is determined to be in a fastening state, a predetermined value set in advance corresponding to the magnitude of oil vibration in which engine rotation affects the durability of the hydraulic switch During the above, the pressure regulating valve is set to a pressure regulating state so as to maintain the output of the pressure regulating valve of the fastening element determined to be in the fastening state lower than the line pressure , and while the engine rotation is less than the predetermined value, A hydraulic control device for an automatic transmission , further comprising protection control means for keeping the output of the pressure regulating valve of the fastening element as the line pressure. 3. The hydraulic control device for an automatic transmission according to claim 1 , wherein the pressure regulating valve includes a spool and forms a throttle with respect to the line pressure in the pressure regulating state .

Images